Gear change mechanisms

ABSTRACT

A manual control device for a fluid-pressure actuated gear change mechanism, said device comprising a hand lever, movable in at least two directions in a valve housing containing at least four valves, and a casing adapted to be secured to a gearbox and housing at least four cylinders, each of said cylinders being connected via one of said valves to a source of pressure fluid; wherein movement of the hand lever to a position to select a gear is effective to exhaust the pressure fluid from at least one of the cylinders and the pressure fluid acting on pistons in the remaining cylinders being effective to select the said gear and to maintain the hand lever in the selected bar position.

United States Patent [72} lnventors Wilbur Mills Page;

Ralph Coupland, both of Lincoln, England [21] Appl. No. 793,456 [22] Filed Jan. 23, 1969 [45] Patented Aug. 24, 1971 {73] Assignee Clayton Dewandre Company Limited Lincoln, Enghmd [32} Priority Jan. 26, 1968 {33] Great Britain [31 4,175/68 [54] GEAR CHANGE MECHANISMS 5 Claims, 6 Drawing Figs.

[52] US. Cl 137/5962, 137/6362, 73/473 [51] 1nt.Cl ..F16kl1/l8, 005g 13/00 [50] Field of Search 192/35; 74/471, 473; 137/596, 596.1, 596.2, 6362, 609, 595

[56] References Cited UNITED STATES PATENTS 2,671,433 3/1954 Meddock 137/5962 X 2,705,971 4/1955 Dorkins 137/6362 3,353,554 11/1967 Ludkin 137/609 X 3,353,555 11/1967 Ludkin 137/5962 3,401 ,574 9/1968 Doolittle 74/473 X FOREIGN PATENTS 564,361 6/1957 Italy 74/471 Primary Examinerl-lenry T. Klinksiek Attorney-Norris & Bateman ABSTRACT: A manual control device for a fluid-pressure actuated gear change mechanism, said device comprising a hand lever, movable in at least two directions in a valve housing containing at least four valves, and a casing adapted to be secured to a gearbox and housing at least four cylinders, each of said cylinders being connected via one of said valves to a source of pressure fluid; wherein movement of the hand lever to a'position to select a gear is efiective to exhaust the pres sure fluid from at least one of the cylinders and the pressure fluid acting on pistons in the remaining cylinders being effective to select the said gear and to maintain the hand lever in the selected bar position.

PATENTED AUG24 l97| SHEET 1 BF 5 INVENTORS WILBUR MILLS PAGE & RALPH COUPLA! BY Mm w Q amom PATENTED AUG24 um SHEET 2 OF 5 iNVENTORS WILBUR MILLS PAGE &

v RALPH CUPLAND BY W PATENTEU AUGZMHTI 3,601( 153 sum 3 OF 5 FIG.

INVENTORS RALPH COUPLAND & WILBUR MILLS PAGE GEAR CHANGE MECHANISMS This invention relates to the manual control of fluid pressure actuated gear change mechanisms.

According to the invention, there is provided a manual control device for a fluid-pressure actuated gear change mechanism, said device comprising a hand lever, movable in at least two directions in a valve housing containing at least four valves, and a casing adapted to be secured to a gearbox and housing at least four cylinders, each of said cylinders being connected via one of said valves to a source of pressure fluid; movement of the hand lever to a position to select a gear being effective to exhaust the pressure fluid from at least one of the cylinders and the pressure fluid acting on pistons in the remaining cylinders being effective to select the said gear and to maintain the hand leverin the selected gear position.

Preferably, the valves are arranged in pairs, the valves of each pair being on a common axis and each valve including a piston arranged to bear against a member formed on or connected to the hand lever or an extension thereof. When only four valves are provided, the two axes are desirably at right angles to each other with one axis vertically above the other.

The hand lever is preferably mounted for pivotal movement in one direction about a shaft provided in the valve housing and for pivotal movement in a second direction about a sleeve located in bores housing the upper two valves.

The cylinders are also desirably arranged in pairs with the cylinders of each pair on a common axis. In the case of four cylinders, the two axes are preferably at right angles to each other.

According to a preferred embodiment, each of the cylinders contains a piston operatively connected to a gearbox striker, operation of the hand lever to a selected gear position being effective to cause at least one of the pistons to move the gearbox striker to select the selected gear in the associated gearbox.

The invention will now be further described, by way of example, with reference to the accompanying drawings in which:

FIG. 1 is a plan view of one example of a valve housing for use in the manual control device according to the present invention;

FIG. 2 is a section on line IIII in FIG. 1;

FIG. 3 is a section on line III-III in FIG. 1;

FIG. 4 is a plan view of one example of a casing for the cylinders used in the manual control device according to the invention;

FIG. 5 is a section on line V-V in FIG. 4; and

FIG. 6 is a section on line VI-VI in FIG. 4.

Referring first to FIGS. 1 to 3 of the drawings, the manual control device comprises a valve housing 11 which is designed to be normally mounted below the floor of a vehicle on a baseplate above the engine. A hand or gear lever 12, corresponding to the lever of a conventional manually operated gearbox is arranged to project through the floor of the vehicle and is mounted in the housing in a manner to be hereinafter described. The housing is closed at its upper side by a cover 13 forming the conventional gate and the gear lever extends through the gate in the normal manner. The gate comprises a main slot in which the gear lever is located for neutral and three branch slots extend from each side of the main slot. Four of the branch slots extend from the ends of the main slot on each side and the remaining two branch slots extend from the center of each side of the main slot. The branch slots provide for gear selection and thus provide five forward gear (indicated respectively as l, 2, 3, 4 and 5) and one reverse gear (indicated as R) positions.

The valve housing is formed with a central chamber 14 from which two pairs of bores l5, l6 and 17, 18 depend. The bores of each of the pairs are on a common axis and the two axes are disposed in planes at right angles to each other. One pair 15, 16 of the bores is located above the other pair 17, 18. The gear lever 12 is pivotally mounted on a shaft 19 in the central chamber 14 above the upper pair of bores l5, l6 and an extension 20 of the gear lever below the shaft 19 is mounted around a cylindrical sleeve 22 the'ends of which are received in the ends of the bores l5, 16. The axes of the shaft 19 and sleeve 22 are disposed in planes at right angles to each other so that the gear lever 12 is capable of pivotal or rockable movement in the direction of the main slot 10 and in the direction of each of the branch slots of the gate.

Each of the bores l5, 16 contains a valve, the valve in bore 15 (hereinafter referred to as valve A) comprising a piston 23, the head of which is slidably received in the cylindrical sleeve 22. The outer end of the piston skirt is of increased diameter and is in sliding engagement with the wall of the bore 15. A seal 24 is provided between this increased diameter, portion and the bore wall. A valve member 25 is provided in the piston 23 and is urged by a spring 26 against a valve seat 27 secured to the inside of the piston 23 adjacent its outer end. A seal 28 is provided between the inside of the piston 23 and the valve member 25 which desirably is hollow and is provided with a tubular extension 29 extending through the valve seat 27. The end of the bore 15 remote from the sleeve 22 is closed by a plug 30 having a port 31 connected to a source of pressure fluid and a second port 32 connected by a fluid line to the cylinder casing in a manner to be hereinafter described. The piston skirt is provided with a number of bores 33 leading to a chamber 34 formed between the piston 23 and wall of bore 15 and an exhaust port (not shown) atmosphere. I ,g r I The valve in the other bore 16 of the upper pair is identical to valve A and this valve will hereinafter be referred to as valve B. This other bore contains a piston 37 and is closed bya plug 38 having two ports connected to the pressure fluid source and cylinder casing.

A lug 2 1 is formed on the hand lever 12 below the shaft 1 9 and this lug is arranged to lie substantially on the axis of the cylindrical sleeve 22. The pressure fluid source acts on the pistons 23, 37 in the two upper bores 15, 16 to force the piston crowns or extensions formed on the piston crowns against the lug 21 when the gear lever 12 is in its neutral position. In this position, the valve members 25 are urged onto their seatings by the associated springs. The valve seats 27 need not be secured to the pistons 23, 37 but may if desired be forced againsta step 35 formed on the inside of each piston by a spring 36 the other end of which bears against the associated plug 30, 38.

' Each of the bores 17, 18 of the lower pair also contains a valve, the valve in the bore 17 (hereinafter referred to as valve C) comprising a piston 41 slideably mounted in a reduced diameter portion 42 of the bore 17 at one end thereof. The outer end of the piston sltirt is of increased diameter and sealingly engages with the wall of the major unreduced diameter portion of the bore 17, a seal 43 being provided between the increased diameter portion of the piston and the bore wall.

A valve member 44 housed within the piston 41 bears, by

means of a spring 45, against a valve seat 46 which is urged bya spring 47 against a step 48 formed on the piston 41. An extension 49 of the valve member passes through the valve seat-z 46 and the valve member is desirably hollow. A seal 50 is provided between the valve member 44 and the inside of the piston wall. The end of the bore 17 is closed by a plug 51 against which the valve seat spring 47 bears. The plug, 51' is provided with two ports 52, 53 connected by fluid lines respectively to the pressure fluid source and gearbox The piston skirt is provided with a number of bores 54 and the bore 17 is provided with an exhaust port 55 leading to atmosphere via a filter 40. Except for the increased diameter portion, a clearanceis provided between the piston skirt and the major portion of the bore wall.

The valve in the other bore 18 of the lower pair is identical to valve C and this valve will be referred to as valve D. The other bore 33 contains a piston 56 and is closed by a plug 57 having ports connected to the pressure fluid source and gearbox.

leads from the chamber to Formed below the extension 20 of the gear lever 12 which fits around the cylindrical sleeve 22 is a lug 58 arranged to lie substantially on the axis of the lower bores 17, 18. The pressure fluid source acts on the pistons 41, S6 in the two lower bores 17, 18 to force the pistons against steps formed by the reduced diameter portions of the lower bores and to hold the piston crowns or extensions formed thereon against this lower lug 58 when the gear lever 12 is in the center of the main slot in the gate. In this position the valve members of valves C and D are urged against their respective valve seats by the associated springs.

The ports leading from valves A to D each lead to an associated cylinder, hereinafter referred to respectively as cylinders A, B, C and D, the four cylinders being formed in a cylinder casing or housing 60 (FIG. 4) adapted to be mounted on top of the gearbox in place of the conventional mechanical gear shift unit.

Turning now to FIGS. 410 6 of the accompanying drawings, the cylinder A is stepped the outer end being of larger diameter than the inner end. A stepped piston 61 is reciprocably mounted in the cylinder and an extension 62 formed on the crown of the piston is arranged to project beyond the inner end of the cylinder when the piston is at one end of its stroke. The outer'end of cylinder A is closed by a cover 63 except for a port 64 connected by a fluid line to the port 32 of valve A. A

further step65 is provided in the cylinder wall of a diameter greater than the inner end but less than the outer end and a port. 66 is provided in this portion of the cylinder leading to the pressure fluid source. Seals 67, 68 are provided between the piston and cylinder walls.

Secured to the crown extension 62 is one end of a shaft 70 the other end of which extends through a bore 71 into cylinder B the diameter of which is equal to the diameter of the outer end of cylinder A. A piston 72 is reciprocably received in the cylinder B and is secured by a screw 73 to a pin 74 which is slidably housed in a socket 75 provided in the other end of the shaft 70. Cylinder B is closed at its inner end except for the bore 71 in which the shaft 70 is slidable and a vent port 71a. The outer end of cylinder B is closed by a cover 76 having a port 77 connected by a fluid line to valve B. A seal 78 is provided between the piston and cylinder walls.

A gearbox striker 80 is pivotally mounted on the shaft 70 intermediate its ends and is adapted to be connected in the usual manner to the selector forks in the gearbox. The gearbox striker is located in a chamber 81 which is closed at the top by a cover 82.

Cylinder C is closed at one end by a cover 83 having a port 84 connected by a fluid line to port 53 of valve C and the cylinder houses a piston 85 secured to a shaft 36 which extends through a bore 87 in the other end of the cylinder. A seal 88 is provided between the piston and cylinder walls. An arm 89 is slidably mounted on the shaft 86 and is arranged to contact one side of the gearbox striker 80.

The other side of the gearbox striker 80 is contacted by a second arm 90 which is secured to the first arm and to a stepped piston 91 reciprocably mounted in cylinder D. Cylinder D is also stepped and the smaller step portion 92 slidingly engages the wall of the piston 91 adjacent the crown. The edge of the piston skirt is of increased diameter to engage slidingly with the larger step portion 93 of the cylinder. Seals 94, 95 are provided between the piston and cylinder walls and the larger end of the cylinder is closed by a cover 96 having a port" 97 connected by a fluid line to valve D. A further step 93 is provided in the cylinder wall between the larger and smaller steps and a port 99 is provided in said cylinder wall at this point leading to the pressure fluid source.

The operation of the control device according to the invention will now be described and it will be assumed that the gear lever 12 is initially in the center of the main slot 10.

When it is desired to select lst gear, the gear lever 12 is first moved to one end of the main slot opposite branch slots 1 and R. The gear lever 12 pivots on the cylindrical sleeve 22 and the lug 58 below the sleeve acts on the piston 41 in valve C to force it towards the plug 51 at the end of the bore 17. When the piston has travelled a predetermined distance, the valve member extension 49 engages a valve seat 59 on the port 52 connected to the fluid pressure source and cuts off the supply of fluid to the bore 17 and hence to the cylinder C. Further movement of the piston 41 brings the valve seat 46 out of engagement with the valve member 44 and the fluid pressure in cylinder C is thus exhausted via ports 84 and 53 through bores 54 to exhaust port 55 and hence to atmosphere.

Cylinder D is still pressurized and the piston 91 in this cylinder is therefore forced towards cylinder C the second arm 90 moving the gearbox striker and hence the first arm 89. The first arm 89 in turn forces the piston in cylinder Caway from cylinder D to expel the pressure fluid from said cylinder C through valve C to atmosphere.

First gear can now be selected by moving the gear lever 12 into the branch slot 1 by pivoting said lever on the shaft 19. When this occurs, the upper lug 21 on the gear lever forces the piston 37 in valve B towards the plug 38 at the end of the bore. Again, the valve member extension 29 engages a valve seat 39 on the port 31 connected to the fluid pressure source and the valve seat 27 on the piston 37 breaks contact with the valve member 25 to connect cylinder B to atmosphere through valve B.

Since cylinder A is still-pressurized, the piston 61 in this cylinder is forced towards cylinder B and the piston 72 in cylinder B is forced by the connected shaft 70 to expel the pressure fluid from cylinder B through valve 8 to atmosphere. The gearbox striker 80 which is mounted on the shaft 70 also moves to select first gear in the associated gearbox. At the same time, valve A forces its piston 23 against the upper lug 21 on the gear lever 12 to maintain said lever in the first-gear branch slot 1. p

When it is desired to return to neutral or to engage 2nd gear, the gear lever 12 must first be moved out of the branch slot 1. The upper lug 21 on the gear lever 12 forces the piston 23 in valve A back to its former position and releases the force on valve B. Since the valve member 25 is hollow, the inside of the piston 37 in valve B is acted on by the fluid pressure source from port 31 so that the piston 37 follows the movement of the gear lever lug 21. When the gear lever 12 has been returned to the main slot 10, the valve member of valve B is again in engagement with the valve seat on the piston 37 and out of engagement with the valve seat on the port 31.

Cylinder B is therefore again pressurized but since this cylinder has a diameter equal to the largest step of cylinder A which is at the same pressure a further force is required to return the cylinders to the central or neutral position. This force is provided by the pressure fluid source which enters cylinder A through the port as in the intermediate step portion 65. This pressure acts on the larger step of the piston 61 in cylinder A and is effective, together with the force on the piston 72 in cylinder B to return the gearbox striker 80 to the neutral position. In this position, the piston 72 in cylinder B bears against the inner end of said cylinder.

The gear lever 12 is then moved to its central position in the main slot 10. The piston 41 in valve C follows the movement of the lug 58 in a similar manner to the piston 37 in valve B and when the gear lever 12 is again in its central position, cylinder C is reconnected to the fluid pressure source via ports 52 and 53in valve C. The force of pressure fluid on the piston 85 in cylinder C, assisted by the force of pressure fluid on the step of the piston in cylinder D which is supplied from the port 99 in the intermediate step portion 98 in said cylinder D, is effective to return the gearbox striker 80, via the arms 89, to its central position. Again, in this position, the piston 85 in cylinder C bears against the inner end of said cylinder.

lf neutral is desired the gear lever 12 may be left in this position. However, if second gear is desired, the gear lever is moved into the gear branch slot 2 which is on the opposite side of the main slot 10 from the gear branch slot 1. In this case valve A is acted on by the gear lever upper lug 21 and cylinder A is connected to atmosphere via ports 64 and 32, bores 33,

chamber 34 and its exhaust port. Since the piston 72 in cylinder B is already at the end of its cylinder it cannot act on the piston 62 in cylinder A. However, the pressure fluid from the port 66 in the intermediate step portion 65 in cylinder A acts on the piston 61 to force it to the end of said cylinder A. The shaft 70 moves with the piston and slides partially out of the pin 74 connnected to the piston 72 in cylinders B and the gearbox striker 80 moves with the shaft 70 to select second gear. The gear lever 12 is maintained in the branch slot 2 by the piston 37 in valve B.

Third gear is selected by first running the gear lever 12 to the central position in the main slot facing both the second and third gear branch slots. When this occurs, valve A again connects cylinder A to the pressure fluid source and the pressure fluid acting on the whole area of the piston 61 in cylinder A returns the piston and hence the gearbox striker 80 to the neutral position, the shaft 70 sliding back to receive the pin 74 connected to the piston 72 in cylinder B. Third gear is then selected by moving the gear lever into the third gear branch slot 3 when the valve B opens cylinder B to atmosphere and third gear is selected as for first gear.

When it is desired to select fourth gear from third gear, the gear lever 12 must first be returned to the main slot 10, when the gearbox striker 80 is returned to neutral as with first gear, and then moved to the end of the main slot opposite branch slots 4 and 5. This movement causes valve D to open cylinder D to atmosphere Since the piston 85 in cylinder C is already bearing on the end of the cylinder it cannot act on the piston 91 in cylinder D. However, the pressure fluid supplied from the port 99 in the intermediate step portion 98 in cylinder D acts on the stepped portion of the piston 91 in cylinder D to move said piston away from cylinder C to expel the pressure fluid in cylinder D through valve D to atmosphere. The second arm 90 moves with the piston in cylinder D and, since the first arm 89 is connected to the second arm 90, said first arm 89 also moves sliding along a reduced diameter portion 79 of the shaft 86 and moving the gearbox striker 80 therewith.

Fourth or fifth gear can now be selected by moving the hand lever into branch slots 4 or 5, the operation being the same as for second and third gears respectively.

When it is desired to reengage neutral or to change to a lower gear, the gear lever is first moved from the gear branch slot 4 or 5 to the main slot 10 and then to the central position in the main slot. The first movement has the same operation as for moving the gear lever 12 out of the second or third gear branch slots 2 or 3 but as regards the second movement, the valve member in valve D again seats on the valve seat in the piston 56 and cuts off cylinder D from atmosphere while at the same time reconnecting the pressure fluid source to cylinder D. The pressure fluid acting on the whole area of the piston 91 in cylinder D returns said piston, against the action of the pressure fluid on the piston step, to its former position. The second arm 90 returns the gearbox striker 80 to its neutral position and the first arm 89 slides back on the portion 79 until it abuts the step formed by the remainder of shaft 86.

Movement of the gear lever 12 is opposed by the air pressure loading behind the valve pistons so that a baulk is provided in either direction when the gear lever is moved from its central neutral position. This gives a good indication as to which gear position is about to be engaged and also prevents a rapid movement from say first to fourth gears instead of from first to second.

Reverse gear is selected in a similar manner to first gear except that cylinder A instead of cylinder B is connected to atmosphere. Means are desirably provided to prevent reverse gear from being selected accidentally. These means may comprise a tube 6 mounted on the gear lever 12 which is arranged to abut against a baulk 17 on the gate cover 13 when reverse gear is to be selected. This baulk may be overcome by lifting the tube 6 against the action of a spring 8 so that it clears the baulk 7.

The exhaust ports in the valve housing are preferably provided with filters 40 to prevent the ingress of dirt etc. into the valves. Moreover, a cover 9 of flexible material such as rubber or plastics is desirably provided over the gate cover, the gear lever 12 and tube 6 extending through the cover in the normal way.

The valve housing preferably includes clutch interlock means whereby a gear position cannot be engaged until the clutch pedal of a vehicle fitted with the device is depressed. The clutch interlock means desirably comprises a piston 101 slidably received in a cylinder 102 in the valve housing 10 and normally urged by a spring 103 to project into the upper bore 15 to prevent movement of the pistons in valves A and B. When the clutch pedal is depressed, the clutch piston 101 is forced out of the bore 15 against the action of spring 103 so that the required gear may be selected.

We claim:

1. A manual control device for a fluid-pressure actuated gear change mechanism, said device comprising a housing containing at least four valves arranged in opposing pairs, each valve including a piston; a hand lever mounted in said housing, said hand lever being movable in at least two directions and being engageable with said valve pistons; a casing adapted to be secured to a gearbox and having at least four cylinders, said cylinders being arranged in pairs and each cylinder having a piston and at least one fluid port; and pressure fluid lines connecting each of said cylinders to a respective valve; each of said pistons in the valve housing containing a valve member arranged to engage a valve seat on the piston in one position of the valve and to engage a second valve seat in a second position of the valve when said piston is engaged and displaced by the hand lever, the valve member in said second position connecting the associated cylinder to atmosphere via the respective pressure fluid connecting line, and said hand lever being movable to engage a valve piston in order to select a gear in said gearbox and being held in said gear-selected position by pressure fluid acting on the opposing valve piston of the pair.

2. A device as claimed in claim 1, the valves of each pair lying on a common axis and the two axes being disposed in planes that are at right angles to each other with one axis arranged vertically above the other.

3. A device as claimed in claim 1, in which the casing contains four cylinders arranged in pairs, the cylinders of each pair lying on a common axis.

4. A device as claimed in claim 3, in which the two axes are disposed in planes that are at right angles to each other.

5. A device as claimed in claim 3, in which the piston in each cylinder is arranged to act on a gearbox striker, whereby operation of the hand lever to a selected gear position is effective to cause at least one of the pistons to move the gearbox striker to select the selected gear in the associated gearbox. 

1. A manual control device for a fluid-pressure actuated gear change mechanism, said device comprising a housing containing at least four valves arranged in opposing pairs, each valve including a piston; a hand lever mounted in said housing, said hand lever being movable in at least two directions and being engageable with said valve pistons; a casing adapted to be secured to a Gearbox and having at least four cylinders, said cylinders being arranged in pairs and each cylinder having a piston and at least one fluid port; and pressure fluid lines connecting each of said cylinders to a respective valve; each of said pistons in the valve housing containing a valve member arranged to engage a valve seat on the piston in one position of the valve and to engage a second valve seat in a second position of the valve when said piston is engaged and displaced by the hand lever, the valve member in said second position connecting the associated cylinder to atmosphere via the respective pressure fluid connecting line, and said hand lever being movable to engage a valve piston in order to select a gear in said gearbox and being held in said gear-selected position by pressure fluid acting on the opposing valve piston of the pair.
 2. A device as claimed in claim 1, the valves of each pair lying on a common axis and the two axes being disposed in planes that are at right angles to each other with one axis arranged vertically above the other.
 3. A device as claimed in claim 1, in which the casing contains four cylinders arranged in pairs, the cylinders of each pair lying on a common axis.
 4. A device as claimed in claim 3, in which the two axes are disposed in planes that are at right angles to each other.
 5. A device as claimed in claim 3, in which the piston in each cylinder is arranged to act on a gearbox striker, whereby operation of the hand lever to a selected gear position is effective to cause at least one of the pistons to move the gearbox striker to select the selected gear in the associated gearbox. 